Location estimation system and location estimation method

Abstract

To provide a technology capable of accurately estimating a position of a vehicle.SOLUTION: One representative location estimation system of the present disclosure comprises: a railway track information storage unit for storing a railway track information database including the railway track shape at each point on a railway track; a railway track shape measuring unit performing measurement of the railway track shape at least twice, in a train traveling on the railway track; a position measuring unit measuring a position of the train on the railway track; a section determination unit determining a matching section in the railway track information database based on the position measured by the position measuring unit; and a railway track information matching unit for matching, in the matching section, a DB railway track shape that is a railway track shape included in the railway track information database with a measured railway track shape that is the railway track shape measured by the railway track shape measuring unit, and estimates a point on the railway track corresponding to the matched railway track shape as the position of the train on the railway track.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a position estimation system and a position estimation method.

Background Art

[0002] In order to realize obstacle detection and advanced train control, which are basic functions of autonomous driving for mobility such as railways and automobiles, it is necessary to estimate the position of the own vehicle with high accuracy. As a conventional method, for example, in the railway field, there is a method in which transponders recording accurate absolute positions are installed on the track, and position correction is performed using information transmitted from the transponders. However, installation of transponders on the track incurs a large burden in terms of installation and maintenance costs.

[0003] Patent Document 1 discloses a traveling position detection system for a railway vehicle that can detect the traveling position of the own vehicle by comparing the shape of a curved section that the railway vehicle has just passed with the shape of any curved section among all curved sections that the railway vehicle can pass through. In this system, first, a passing curve information creation unit 40 creates passing curve information R including actually measured values such as an actually measured curvature radius every time the vehicle passes through a curved section. In addition, a candidate curve information group creation unit 50A creates each candidate curve information group G, which is a collection of candidate curve information K corresponding to all passable curved sections. Next, a coincidence rate calculation unit 60 calculates a total coincidence rate J that indicates how much the immediately previous passing curve information and the passing curve information before that match each candidate curve information group G within the range from 0 to 1. Finally, a curve specification unit 70 compares the total coincidence rates J calculated for each candidate curve information group G to specify the curved section that has just been passed.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] In some cases, railway tracks are laid in a way that minimizes changes in their shape. In such cases, the method described in Patent Document 1 may have difficulty detecting differences in track shape, making accurate position estimation challenging. Therefore, there is a need for a method that can accurately estimate the position even when track shape changes are small and matching the track shape is difficult. Therefore, the objective of this invention is to provide a technology that can accurately estimate the position of a train. [Means for solving the problem]

[0006] To solve the above problems, one representative position estimation system of the present invention includes: a track information storage unit that stores a track information database including the track shape of each point on the track; a track shape measurement unit that measures the track shape at least twice when a train is running on the track; a position measurement unit that measures the position of the train on the track; a section determination unit that determines a matching section in the track information database based on the position measured by the position measurement unit; and a track information matching unit that, in the matching section, compares the DB track shape, which is the track shape included in the track information database, with the measured track shape, which is the track shape measured by the track shape measurement unit, and estimates the point on the track corresponding to the matched track shape as the position of the train on the track. [Effects of the Invention]

[0007] According to the present invention, the position of a train can be estimated with high accuracy. Issues, structures, and effects other than those mentioned above will be clarified by the following explanation of the implementation methods. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows a position estimation system according to the first embodiment. [Figure 2] Figure 2 shows an example of a railway track information database. [Figure 3]Figure 3 is a schematic diagram illustrating the method for determining the matching interval. [Figure 4] Figure 4 shows a method for estimating the position of a train using the track shape at the current location of each vehicle and a database of matching sections. [Figure 5] Figure 5 is a flowchart showing the position estimation in the first embodiment. [Figure 6] Figure 6 shows an example of the estimated number of positions and the results of the matching process. [Figure 7] Figure 7 shows a position estimation system according to the second embodiment. [Figure 8] Figure 8 shows a method for measuring track geometry and matching it with a database over time. [Figure 9] Figure 9 shows an example of a track information database in the third embodiment. [Figure 10] Figure 10 shows a method for measuring track shape and verifying it against the database when the track information database contains continuous data. [Modes for carrying out the invention]

[0009] [First Embodiment] In the first embodiment, a method for estimating the position of a train is described by performing measurement of the track shape and matching it with a track information database at multiple locations.

[0010] First, we will explain the configuration of the position estimation system and the role of each component using Figure 1.

[0011] (System configuration) Figure 1 shows a position estimation system 100 according to the first embodiment. The position estimation system 100 according to the first embodiment includes a first track shape measurement unit 101, a second track shape measurement unit 102, a position measurement unit 103, a track information storage unit 104, a section determination unit 105, and a track shape matching unit 106. The information of the train's position estimated by the position estimation system 100 is output to the vehicle control unit 107, and the vehicle control unit 107 controls the train based on the train's position.

[0012] The track shape measurement units 101 and 102 measure the track shape at least twice when a train is running on the tracks. The track shape measurement units are installed in one of the cars that make up the train, and each has the function of measuring the track shape at the current location of the car in which it is installed. In the first embodiment, two track shape measurement units are provided, the first track shape measurement unit 101 and the second track shape measurement unit 102, and each performs at least one measurement, for a total of at least two measurements. The first track shape measurement unit 101 outputs information Sg1 indicating the track shape measured in the first car to the track shape matching unit 106, and the second track shape measurement unit 102 outputs information Sg2 indicating the track shape measured in the second car to the track shape matching unit 106.

[0013] Information indicating track shape includes, in addition to basic track information such as track gradient values and track curve radii, characteristic track information such as irregularities at rail joints, which are also included as information indicating track shape in a broad sense. For example, for a gradient amount, a sensor capable of measuring a pitch angle such as a level is used. In the following description, explanation will be given using a gradient amount as an example of a track shape; however, the first embodiment is not limited thereto, and can also be applied when other track shapes such as a curve radius or a rail joint are used, or when a plurality of pieces of information are used in combination. Furthermore, the sensor is not limited to a level. For example, a gyro sensor or an angular velocity sensor may be used, or a combination of these sensors may be used. It is also possible to measure the state of the vehicle by a three-dimensional measuring sensor, and calculate the gradient amount, the curve radius, and the rail joint. Alternatively, track information may be extracted using information obtained by an optical sensor such as LIDAR (light detection and ranging) or a camera, or the track shape may be measured using satellite information such as GNSS (Global Navigation Satellite System).

[0014] In addition, when selecting a vehicle for measuring track information, for example, the leading vehicle is used as the first track shape The first vehicle on which the measurement unit 101 is installed, and the rearmost vehicle is used as the second vehicle on which the second track shape measurement unit 102 is installed. Selecting vehicles separated by a distance tends to cause differences in the measured track information, so even if accurate estimation cannot be performed using track information from only one vehicle, it is expected that the accuracy of position estimation will be improved by using track information from two vehicles. Furthermore, vehicles for which track information cannot be measured accurately due to the influence of suspension or the like may be excluded from selection targets of vehicles for measuring track information.

[0015] Note that the number of vehicles for measuring the track shape is at least two including the leading vehicle and the trailing vehicle among the plurality of vehicles, but it is not limited to two and may be three or more. In addition, the case where the track shape measurement unit is not installed for each vehicle is also included in addition to the case where it is installed for each vehicle. For example, a sensor may be installed on each vehicle to measure the state of the vehicle, information indicating the measured state of the vehicle may be analyzed by the track shape measurement unit, and the track shape of each vehicle may be calculated.

[0016] The position measurement unit 103 has a function of measuring the position of the train on the track. Since the position calculated herein may include errors and the like, it is an approximate position of the train (hereinafter also referred to as "approximate position"). Examples of means for measuring the approximate position of the train include a position calculated from an integrated value of a speedometer of the train, and a method using information between traveling stations of the train. The position measurement unit 103 can measure the approximate position of the train or the approximate position of each vehicle based on information of vehicles forming the train. The position measurement unit 103 outputs information Sg3 indicating the approximate position of the train or the approximate position of each vehicle to the section determination unit 105. Note that the means for measuring the approximate position is not limited to a speedometer. For example, by photographing the track and objects around the track, oh the approximate position may be acquired by matching images obtained by photographing the track and the environment around the track using LIDAR and a camera. In addition, the measurement of the approximate position is continuously performed while the train is traveling, and it is possible to calculate the approximate position at the timing of measurement performed by the first track shape measurement unit 101 and the second track shape measurement unit 102.

[0017] The track information storage unit 104 has the function of storing a track information database that includes the track shape at each point along the track. Figure 2 shows an example of the track information database DB1. In this example, the track information database DB1 has the following items: location, gradient amount at each point, curve radius, and presence or absence of rail joints. Although an example is shown that includes gradient amount, curve radius, and presence or absence of rail joints as track shape, it is not limited to these, and other information indicating track shape may be stored. Furthermore, any information indicating the condition of the track can be stored as information indicating track shape in a broad sense. The track information storage unit 104 outputs information Sg4 indicating the track information database to the section determination unit 105. Alternatively, the section determination unit 105 may be configured to appropriately refer to the track shape database stored in the track information storage unit 104.

[0018] Furthermore, if the values ​​in the track information database differ depending on the vehicle even at the same location, separate databases may be maintained and used for each vehicle. Be Factors that could cause differences in measurements include, for example, variations in the suspension of individual vehicles.

[0019] Furthermore, when creating the track information database, it is possible to create it not only from the measurement results of a single train, but also by combining the measurement results of multiple trains. For example, it is possible to apply the position estimation system according to the first embodiment to a train operation management system and reflect the track shape and approximate position measured for multiple trains in the track information database.

[0020] The section determination unit 105 determines the matching section in the track information database based on the positions measured by the first track shape measurement unit 101 and the second track shape measurement unit 102. The section determination unit 105 has the function of determining the section to be used for matching the track shape (hereinafter referred to as the "matching section") from the information Sg4, which shows the track information data for each point output from the track information storage unit 104, using the approximate position output from the position measurement unit 103. The matching section may be determined to be the section before or after the approximate position. The length of the section before and after the approximate position is determined according to the required performance such as the accuracy of position estimation and the time required for estimation. The section determination unit 105 outputs information Sg5, which shows the determined matching section, to the track shape matching unit 106.

[0021] Here, we will explain in detail how to determine the matching interval. Figure 3 is a schematic diagram illustrating the method for determining the matching interval.

[0022] Let's consider the case where the position measurement unit 103 measures the approximate position of the first vehicle as point x4 and the approximate position of the second vehicle as point x3. In step S1, the section determination unit 105 receives information Sg3 indicating the approximate position of each vehicle and searches for a location in the track information database that corresponds to the approximate position. As a search method, for example, there is a linear algorithm method that searches sequentially from the beginning of the database, and other methods can be selected as appropriate.

[0023] Note that the track information database DB1 shown in Figure 3 has discrete values. On the other hand, the estimated vehicle position takes continuous values, and there may be cases where a simple search is not possible. In this case, the section determination unit 105 searches for the point among the points included in the track information database DB1 that is closest to the position measured by the position measurement unit. For example, the difference between the point in the track information database and the point indicated by the estimated position can be taken, and the point with the smallest difference can be used as the search result in step S1.

[0024] In step S2, the interval determination unit 105 determines the matching interval by setting the interval length sl before and after the point searched in step S1. For example, if the interval length sl is large, the amount of work required for subsequent matching processing will increase. On the other hand, if the interval length sl is small, there is a risk that the matching process cannot be performed accurately. The interval length sl is set according to the operation of the system.

[0025] The track shape matching unit 106 has the function of estimating the position of a vehicle by matching the track shape at the current location of each vehicle, output from the first track shape measurement unit 101 and the second track shape measurement unit 102, with the matching section output from the section determination unit 105. For example, in the matching section, the track shape matching unit 106 matches the track shape included in the track shape database (hereinafter also referred to as "DB track shape") with the track shape measured by the first track shape measurement unit 101 and the second track shape measurement unit 102 (hereinafter also referred to as "measured track shape"), and estimates the point on the track corresponding to the matched track shape as the position of the train on the track.

[0026] Figure 4 shows a method for estimating the position of a train using the track shape at the train's current location and a database of matching sections. The first track shape measurement unit 101 is installed in the leading car, which is the first vehicle, and the second track shape measurement unit 102 is installed in the last car, which is the second vehicle. The arrows indicate the direction of travel of the vehicles. Figure 4(a) shows how the track shape is measured. As shown here, the first track shape measurement unit 101 measures the incline θ1, and the second track shape measurement unit 102 measures the incline θ2.

[0027] Figure 4(b) shows how the database matching is performed. The matching interval is set to the range from point x1a to point x6a in database DB2, and the gradient amount at the first track shape measurement unit 101 is θ1, and the gradient amount at the second track shape measurement unit 102 is θ2.

[0028] The track information database DB2 shown in Figure 4(b) is discretely set as points x1a, x2a, ... The interval between points is based on the train length, which is the distance between the first and second vehicles. This track information database DB2 based on train length is based on information Sg3 and which indicates the approximate position of each vehicle in the position measurement unit 103. line Based on the information Sg4 that indicates the information database DB1, the section determination unit 105 creates it. For example, the section determination unit 105 may extract data based on train volume from the track information database DB1 and use that as the database, or it may change the data section of the track information database DB1.

[0029] First, within the matching section, the system searches for points corresponding to the gradient θ1 measured by the first track shape measurement unit 101. The matching results show that points x2a, x3a, x4a, and x6a correspond to the gradient θ1. Next, within the matching section, the system searches for points corresponding to the gradient θ2 measured by the second track shape measurement unit 102. As shown in the matching results, point x3a was found to correspond to the gradient θ2. As a result, within the matching section, points x3a and x4a were found to be the locations corresponding to gradients θ1 and θ2, respectively, and the position of the first vehicle can be estimated to be x4a, and the position of the second vehicle can be estimated to be x3a. In this way, the position can be estimated from the track shape and the matching section. Information Sg6 indicating the estimated position is output to the vehicle control unit 107.

[0030] In the above matching method, even if the values ​​between the track shape and the track information database DB2 do not perfectly match, matching may be considered acceptable and matched as long as the difference is within a pre-set range. Furthermore, the acceptable range may be set according to the accuracy of the position estimation. For example, in the matching process, the difference between the gradient amount in the track information database DB2 and the gradient amounts measured by the first track shape measurement unit 101 and the second track shape measurement unit 102 may be taken, and if the difference is within a pre-set range, it may be considered a match and matched. The pre-set range can be appropriately selected according to the system operation status.

[0031] Furthermore, if the result falls outside the acceptable range and matching is not possible, it will be determined that position estimation using this method is not feasible, and the position will be measured using other position measurement means, or the previous position value will be retained.

[0032] Furthermore, since the measured values ​​of the track shape may fluctuate due to driving operations such as acceleration and deceleration of the vehicle, position estimation may be omitted in sections where the vehicle's driving operations change, or the acceleration and deceleration of the changed driving operations may be taken into account when measuring the track shape. Vehicle driving operations include acceleration (powering), constant speed driving, coasting, and braking.

[0033] The vehicle control unit 107 has the function of controlling the train using the position information Sg6 output from the track shape matching unit 106. Examples of train control methods include automatic train control (ATC) and automatic train operation (ATO).

[0034] The above describes the configuration and components of the position estimation system 100.

[0035] (flowchart) Next, using Figure 5, the procedure for estimating the position in the section from departure from one station to arrival at the next station in the first embodiment will be explained. Figure 5 is a flowchart of the position estimation in the first embodiment. Note that the same procedure is carried out from arrival at the next station until arrival at the final station of the line, and the explanation for that is omitted.

[0036] In step S11, the first track shape measurement unit 101 and the second track shape measurement unit 102 measure track shape information at the current location.

[0037] In step S12, the position measurement unit 103 calculates the approximate position of the vehicle based on the speedometer and current station-to-station information.

[0038] In step S13, the section determination unit 105 determines the matching section using the approximate position of the vehicle output from the position measurement unit 103 and the track information database for each point output from the track information storage unit 104.

[0039] In step S14, the track shape matching unit 106 matches the track shape at the current location of each vehicle, output in step S11, with the matching section output in step S13, and estimates the vehicle's position by searching for a point corresponding to the matched track shape, and updates the estimated position of the vehicle. If matching based on the track shape at the current location is not possible, it is determined that position estimation by this method is not possible. Reasons why track shape matching may not be possible include, in addition to the inability to find a match when searching for a track shape in step S14, the inability to measure track information in step S11, the inability to measure an approximate position in step S12, the inability to determine a matching section in step S13, and so on.

[0040] In step S15, the position estimated in step S14 is output to the vehicle control unit 107, and the vehicle control unit 107 controls the vehicle according to that position information.

[0041] In step S16, it is determined whether the next station has been reached. If not, the process returns to step S11. If the next station has been reached, the process ends.

[0042] Steps S11 to S16 described above are repeated at predetermined time intervals. Figure 6 shows an example of the number of estimation attempts and the results of the matching process. As shown in Figure 6(a), in the 1st, 3rd, 4th, 7th, and 8th estimation attempts, a circle (○) is written in the matching result column, indicating that the location estimation was performed correctly. On the other hand, in the 2nd, 5th, and 6th attempts, a cross (×) is written in the matching result column, indicating that the location estimation was not performed correctly.

[0043] Figure 6(b) shows another example of the estimation and matching process results. Here, A to C are listed in the matching result column. This evaluates the matching process results based on the degree of agreement between the point and track information in the matching section of the database and the approximate position and track information obtained by the first track shape measurement unit 101 and the second track shape measurement unit 102 or position measurement unit 103. For example, a three-stage evaluation criterion is set for the difference between the database value and the measured value, with A representing the case where the difference is smallest and the accuracy of the position estimation result is high, C representing the case where the difference is largest and the accuracy of the position estimation result is low, and B representing a case in between A and C.

[0044] As shown in Figures 6(a) and (b), if a matching result cannot be obtained at a certain point or if the desired accuracy cannot be obtained, it is also possible to interpolate the data using the results from the preceding and succeeding points to estimate the position.

[0045] The above is a description of the procedure for estimating the position using this method in the section from departure from one station to arrival at the next station.

[0046] (Effects / Actions) As explained above, according to the first embodiment, by performing measurement of the track shape and matching with the track information database at multiple locations, accurate position estimation is possible even when the differences in track shapes are small and matching of track shapes is difficult.

[0047] Furthermore, in some cases, the shape of the railway tracks remains relatively consistent throughout the entire line, and multiple sections with similar shapes may appear on the tracks where the train travels. In such cases, simply acquiring and comparing track shape information from a single vehicle may lead to errors in the matching process, such as extracting shapes from the wrong location. By measuring and comparing track shape information from multiple vehicles, the train's position can be estimated with greater accuracy.

[0048] Furthermore, while it is theoretically possible to estimate the location by matching the track shape for all points included in the track information database, this is not practical due to the high processing load and the potential for lengthy location estimation. By limiting the matching section within the track information database, it is possible to reduce the processing load while performing location estimation in a timely manner.

[0049] Furthermore, it is conceivable that railway tracks will be laid on terrain with significant gradient changes. Compared to flat roads, more power is required on uphill slopes, and appropriate braking is necessary on downhill slopes. By accurately estimating the position based on the location and gradient, it is possible to control the vehicle's power generation system, braking system, and operating speed, enabling safe operation of the vehicle.

[0050] Furthermore, when a train travels on a curved track, control is implemented to improve both the passing speed and ride comfort by tilting the train body. By accurately estimating the position based on the location and curvature, the amount, timing, and direction of the train body tilt can be calculated with precision, thereby improving both speed and ride comfort.

[0051] Furthermore, when a train passes over rail joints, vibrations and noise are generated. This affects ride comfort inside the train and the surrounding environment outside. By accurately estimating the train's position based on the location and rail joints, vibration control of the train can be implemented, suppressing the generation of vibrations and noise.

[0052] (Second embodiment) In the second embodiment, a method for estimating the position by measuring the track shape and comparing it with a database over time will be described. Components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions will be omitted.

[0053] In the first embodiment, the accuracy of position estimation was improved by performing track shape measurement and database matching at multiple locations, whereas in the second embodiment, the accuracy of position estimation is improved by performing track shape measurement and database matching over time.

[0054] Therefore, in the first embodiment, multiple vehicles and sensors were required to measure the track shape, whereas in the second embodiment, only one vehicle or sensor is needed for measuring the track shape for the entire train.

[0055] Figure 7 shows a position estimation system 100a according to a second embodiment. In the position estimation system 100a, track information is measured by the first track shape measurement unit 101.

[0056] Figure 8 shows a method for measuring track shape and matching it with a database in a time series. Here, the first track shape measurement unit 101 is installed in the leading vehicle. The first track shape measurement unit 101 measures the track shape at the first time t1 and the second time t2. Figure 8(a) shows the case where the gradient amount θ1 is measured at the first time t1, and Figure 8(b) shows the case where the gradient amount θ2 is measured at the second time t2. Figure 8(c) shows the concept of the matching process performed in the track information database DB3. The track information database DB3 shown in Figure 8(c) is set discretely as points x1b, x2b, ... The interval between points is based on the distance traveled by the vehicle between the first time t1 and the second time t2. The setting of such a track information database DB3 is performed in the section determination unit 105 based on information Sg3 indicating the approximate position of each vehicle in the position measurement unit 103.

[0057] First, within the matching section, we search for points corresponding to the gradient θ1 at the first time step t1. As shown in the matching results, in the track information database DB3, it was found that points x2b, x3b, x4b, and x6b correspond to the gradient θ1. Next, within the matching section, we search for points corresponding to the gradient θ2 at the second time step t2. As shown in the matching results, it was found that point x3b in the track information database DB3 corresponds to the gradient θ2. As a result, within the matching section, the locations corresponding to gradients θ1 and θ2 are found to be points x3b and x4b, so it can be estimated that the location at the first time step t1 is x3b and the location at the second time step t2 is point x4b. The time series of the track information measured in this way strange By using a method that verifies the data, the position can be estimated from the track information and the verifiable section over time.

[0058] In the second embodiment, the number of data points used in the time series was described as two points, the first time point t1 and the second time point t2. However, the method is not limited to this, and position estimation may be performed using three or more data points in the time series.

[0059] (Effects / Actions) As described above, according to the second embodiment, by performing the measurement of the track shape and matching it with the database using multiple measurement values ​​in a time series, accurate position estimation is possible even when the differences in track shapes are small and matching the track shapes is difficult.

[0060] [Third Embodiment] In the first embodiment, a track information database with intervals based on train length was used, and in the second embodiment, a track information database with intervals based on travel distance was used. In both cases, the track information database has a fixed interval, but in the third embodiment, the fixed interval of the track information database is subdivided at specific points. Components identical to those in the first and second embodiments are denoted by the same reference numerals and their descriptions are omitted.

[0061] Figure 9 shows an example of the track information database DB4 in the third embodiment. The track information database DB4 is composed of discrete values, and the intervals between points x1, x2, x3, x4, x5, and x6 are all the same. Here, in region L1, point x1 is subdivided into points x11 and x12 at half the interval, and each item of gradient, radius of curvature, and rail joint has data corresponding to points x11 and x12. Point x2 is also subdivided into points x21 and x22. In region L2, point x3 is subdivided into points x31, x32, and x33 at one-third the interval, and each item of gradient, radius of curvature, and rail joint has data corresponding to points x31, x32, and x33 respectively. Point x4 is also subdivided into points x41, x42, and x43.

[0062] The matching process is carried out in the same manner as in the first and second embodiments.

[0063] (Effects / Actions) While location data in the railway information database is entered as discrete values, locations obtained through approximate location measurements are continuous values. Therefore, achieving a perfect match when cross-referencing the railway information database is difficult.

[0064] In contrast, in the third embodiment, the data intervals in the track information database DB4 are subdivided. This makes it possible to reduce the difference between the position obtained by the measurement of the approximate position and the point in the track information database DB4, thereby improving the accuracy of position estimation.

[0065] Furthermore, for example, when implementing energy-saving operation, it is necessary to accurately detect changes in track shape and control the train accordingly. By selecting locations where track shape changes are significant and pre-subdividing and storing the values ​​in a database, it becomes possible to detect changes in track shape and perform train control that adapts to these changes.

[0066] (Fourth embodiment) The fourth embodiment differs from the first to third embodiments in that the track information database contains continuous data for locations and track shapes. In the following description, components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0067] Figure 10 shows a method for measuring track shape and verifying it against the database when the track information database contains continuous data.

[0068] Figure 10(a) shows the case where the gradient is measured in the fourth embodiment. The first track shape measurement unit 101 is provided in the leading car, and the second track shape measurement unit 102 is provided in the last car.

[0069] Figure 10(b) shows the measured gradient. The gradient θ1 is the gradient measured by the first track shape measuring unit 101. The gradient θ2 is the gradient measured by the second track shape measuring unit. As shown here, in the fourth embodiment, the measurement results from the track shape measuring unit also have continuous values. For example, it is possible to take measurements continuously while the train is running, or to take measurements at specific points.

[0070] Figure 10(c) is a diagram illustrating the concept of matching processing performed in the track information database DB5. As shown here, in the fourth embodiment, the track information database DB5 has a continuous gradient value for the track between station A and station B. In the matching section, a pattern is detected between the gradient value in the track information database DB5 and the gradient value θ1, and a pattern is also detected between the track information database DB5 and the gradient value θ2. The position corresponding to the gradient value matched in either pattern matching is estimated as the position of the train.

[0071] Although the fourth embodiment was described using gradient values, it is not limited to this. It can also be applied to other information indicating track shapes. Furthermore, although the case using two track shape measurement units was shown, similar to the first embodiment, it is not limited to this. It can also be applied when using three or more track shape measurement units. In addition, the fourth embodiment can be applied to matching track shapes over time, as in the second embodiment.

[0072] (Effects / Actions) In the fourth embodiment, the track information database DB5 has continuous track shape data. By using pattern matching in the matching process, the accuracy of the matching process can be improved, and as a result, the accuracy of position estimation can be further improved.

[0073] While embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the gist of this disclosure.

[0074] Although the embodiments have been described separately in this disclosure, it is also possible to combine these embodiments.

[0075] Furthermore, the position estimation system described in this disclosure can be mounted on a train and used as an onboard system. Alternatively, the position estimation system described in this disclosure may be adopted in a train operation management system to perform position estimation and operational control of multiple trains within a track section.

[0076] (Other forms) This disclosure also includes the following aspects: (Aspect 1) A track information storage unit that stores a track information database including the track shape at each point along the railway line, A train traveling on the aforementioned tracks includes a track shape measuring unit that measures the track shape at least twice, A position measuring unit for measuring the position of the aforementioned train on the tracks, A section determination unit determines a matching section in the track information database based on the position measured by the position measurement unit, In the aforementioned matching section, the track information matching unit compares the DB track shape, which is the track shape included in the track information database, with the measured track shape, which is the track shape measured by the track shape measurement unit, and estimates the point on the track corresponding to the matched track shape as the position of the train on the track. A position estimation system that includes this. (Aspect 2) A position estimation system according to Embodiment 1, The section determination unit searches for the point closest to the position measured by the position measurement unit among the points included in the track information database, sets a predetermined section length before and after the searched point, and defines this as the matching section. Location estimation system. (Aspect 3) A position estimation system according to embodiment 1 or 2, The aforementioned train is composed of multiple cars, The track shape measuring unit measures the track shape in at least two of the multiple vehicles. Location estimation system. (Aspect 4) A position estimation system according to any one of embodiments 1 to 3, The aforementioned at least two vehicles include, among the plurality of vehicles, the leading vehicle and the last vehicle. Location estimation system. (Appendix 5) A position estimation system according to any one of embodiments 1 to 4, The track shape measuring unit measures the track shape at the first time and the second time. Location estimation system. (Aspect 6) A position estimation system according to any one of embodiments 1 to 5, The gradient of the track is used as the track shape. Location estimation system. (Aspect 7) A position estimation system according to any one of embodiments 1 to 6, The curve radius of the track is used as the track shape. Location estimation system. (Pattern 8) A position estimation system according to any one of embodiments 1 to 7, The track shape is defined as the presence or absence of irregularities at the joints of the rails of the track. Location estimation system. (Aspect 9) A position estimation system according to any one of embodiments 1 to 8, The position measuring unit calculates the position of the train based on the cumulative value of the train's speedometer. Location estimation system. (Aspect 10) A position estimation system according to any one of embodiments 1 to 9, The aforementioned track information database records track shapes at regular intervals, and at specific points, these regular intervals are subdivided. Location estimation system. (Aspect 11) A method for estimating location using a track information database that includes the track shape at each point along the railway line, A track shape measurement step in which the track shape is measured at least twice in a train traveling on the aforementioned track, A position measurement step for measuring the position of the aforementioned train on the tracks, A section determination step in which a matching section in the track information database is determined based on the position measured in the position measurement step, Track information matching step, in the matching section, compares the DB track shape, which is the track shape included in the track information database, with the measured track shape, which is the track shape measured in the track shape measurement step, and estimates the point on the track corresponding to the matched track shape as the position of the train on the track. A location estimation method that includes [specific details omitted]. [Explanation of symbols]

[0077] 100, 100a: Position estimation system 101: First track shape measurement unit 102: Second track shape measurement unit 103: Position measurement unit 104: Track Information Storage Unit 105: Section Determination Section 106: Track shape matching unit 107: Vehicle Control Unit DB1, DB2, DB3, DB4, DB5: Track Information Database

Claims

1. A position estimation system for estimating the position of a train composed of multiple vehicles on a railway track, In a train traveling on the aforementioned tracks, the first and second cars are equipped with track shape measuring units that measure the track shape at the estimated positions on the tracks, A track information storage unit stores a track information database that records the track shape at each point on the track at intervals of the length between the first and second vehicles, A position measuring unit for measuring the position of the aforementioned train on the tracks, A section determination unit determines a matching section in the track information database based on the position measured by the position measurement unit, In the aforementioned matching section, the track information matching unit includes a track information matching unit that estimates the position of the train on the track at a point in the track information database where the point corresponding to the first measured track shape and the point corresponding to the second measured track shape are separated by the distance between the first and second vehicles in the track information database, based on the first measured track shape measured by the track shape measurement unit at the first vehicle and the second measured track shape measured at the second vehicle. The aforementioned track information database is a position estimation system in which the intervals are subdivided at specific points.

2. A position estimation system according to claim 1, The section determination unit searches for the point closest to the position measured by the position measurement unit among the points included in the track information database, sets a predetermined section length before and after the searched point, and defines this as the matching section. Location estimation system.

3. A position estimation system according to Claim 1, The first vehicle and the second vehicle are the leading vehicle and the trailing vehicle. Location estimation system.

4. A position estimation system according to Claim 1, The gradient of the track is used as the track shape. Location estimation system.

5. A position estimation system according to Claim 1, The curve radius of the track is used as the track shape. Location estimation system.

6. A position estimation system according to Claim 1, The track shape is defined as the presence or absence of irregularities at the joints of the rails of the track. Location estimation system.

7. A position estimation system according to Claim 1, The position measurement unit calculates the position of the train based on the cumulative value of the train's speedometer. Location estimation system.

8. A position estimation method for estimating the position of a train composed of multiple vehicles on a railway track using a railway information database that includes the track shape of each point on the track, A track shape measurement step in which a train traveling on the aforementioned track measures the track shape at the estimated position on the track with the first and second cars, A position measurement step for measuring the position of the aforementioned train on the tracks, A section determination step in which a matching section in the track information database is determined based on the position measured in the position measurement step, In the aforementioned matching section, a track information matching step is performed to estimate the position of the train on the track at a point in the track information database where the point corresponding to the first measured track shape and the point corresponding to the second measured track shape are separated by the distance between the first and second vehicles in the track information database, based on the first measured track shape and the second measured track shape measured in the track shape measurement step. Includes, The aforementioned track information database records the track shape at each point along the track at intervals equal to the length between the first and second vehicles, and at specific points, the interval is subdivided. Location estimation method.

Images